Class OctreeColorQuantizer
java.lang.Object
net.sourceforge.jiu.ops.Operation
net.sourceforge.jiu.ops.ImageToImageOperation
net.sourceforge.jiu.color.quantization.OctreeColorQuantizer
- All Implemented Interfaces:
RGBQuantizer
,RGBIndex
Performs the octree color quantization algorithm for a given RGB truecolor image.
The quality is usually somewhat inferior to the results of
MedianCutQuantizer
.
Note that you can improve the quality by applying a dithering algorithm.
See ErrorDiffusionDithering
.
Usage example
This reduces some RGB24Image image to a 16 color paletted image:MemoryRGB24Image image = ...; // initialize OctreeColorQuantizer ocq = new OctreeColorQuantizer(); ocq.setInputImage(image); ocq.setPaletteSize(16); ocq.process(); PixelImage quantizedImage = ocq.getOutputImage();
Credits
- Since:
- 0.6.0
- Author:
- Marco Schmidt
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate int[]
static final int
The default number of colors in the palette.private int[]
private Palette
private int
private int[]
private OctreeNode
Fields inherited from interface net.sourceforge.jiu.data.RGBIndex
INDEX_BLUE, INDEX_GREEN, INDEX_RED
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprivate int
assignPaletteIndexValues
(OctreeNode node, int index) If node is a leaf node, this method assigns palette index values and determines the representative color, otherwise it simply recursively calls itself for all child nodes.Return a Palette object with the list of colors to be used in the quantization process.void
init()
Creates an octree and prepares this quantizer so that colors can be mapped to palette index values.private int
private void
initPalette
(OctreeNode node, Palette palette) int
map
(int[] origRgb, int[] quantizedRgb) Maps an RGB colororigRgb
to one of the colors in the color map; that color will be written toquantizedRgb
and its palette index will be returned.private void
mapImage()
void
process()
Initializes an octree, reduces it have as many leaves (or less) as the desired palette size and maps the original image to the newly-created palette.private void
Reduces the octree until it has as many leaves (or less) than specified by thepaletteSize
argument in the constructor#OctreeColorQuantizer(int)
.void
setPaletteSize
(int newPaletteSize) Methods inherited from class net.sourceforge.jiu.ops.ImageToImageOperation
canInputAndOutputBeEqual, ensureImagesHaveSameResolution, ensureInputImageIsAvailable, ensureOutputImageResolution, getInputImage, getOutputImage, setCanInputAndOutputBeEqual, setInputImage, setOutputImage
Methods inherited from class net.sourceforge.jiu.ops.Operation
addProgressListener, addProgressListeners, getAbort, removeProgressListener, setAbort, setProgress, setProgress
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Field Details
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DEFAULT_PALETTE_SIZE
public static final int DEFAULT_PALETTE_SIZEThe default number of colors in the palette. Will be used when no other value is specified viasetPaletteSize(int)
.- See Also:
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paletteSize
private int paletteSize -
root
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palette
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redValues
private int[] redValues -
greenValues
private int[] greenValues -
blueValues
private int[] blueValues
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Constructor Details
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OctreeColorQuantizer
public OctreeColorQuantizer()
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Method Details
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assignPaletteIndexValues
If node is a leaf node, this method assigns palette index values and determines the representative color, otherwise it simply recursively calls itself for all child nodes. The updated index value is returned. It is increased whenever a leaf is assigned that index value.- Parameters:
node
- the node of the octree that will itself (and its children) be processedindex
- the current index in the palette index assignment procedure- Returns:
- updated index value; may have been increased while node or its child(ren) - were assigned index values
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createPalette
Description copied from interface:RGBQuantizer
Return a Palette object with the list of colors to be used in the quantization process. That palette may be fixed or created specifically for a given input image.- Specified by:
createPalette
in interfaceRGBQuantizer
- Returns:
- Palette object for destination image
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init
Creates an octree and prepares this quantizer so that colors can be mapped to palette index values. If you useprocess()
you must not call this method. On the other hand, if you want to do the mapping yourself - maybe if you want to do mapping and dithering interchangeably - call this method first, then do the mapping yourself.- Throws:
MissingParameterException
- if parameters like the input image are missingWrongParameterException
- if parameters exist but are of the wrong type
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initOctree
private int initOctree() -
initPalette
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map
public int map(int[] origRgb, int[] quantizedRgb) Maps an RGB colororigRgb
to one of the colors in the color map; that color will be written toquantizedRgb
and its palette index will be returned.- Specified by:
map
in interfaceRGBQuantizer
- Parameters:
origRgb
- the color to be mapped to the best-possible counterpart in the palette; the array is indexed by the constants fromRGBIndex
quantizedRgb
- the resulting color from the palette will be written to this array; it is also indexed by the constants fromRGBIndex
- Returns:
- index of the found color in the palette
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mapImage
private void mapImage() -
process
Initializes an octree, reduces it have as many leaves (or less) as the desired palette size and maps the original image to the newly-created palette.- Overrides:
process
in classOperation
- Throws:
MissingParameterException
- if any mandatory parameter was not given to the operationWrongParameterException
- if at least one of the input parameters was not initialized appropriately (values out of the valid interval, etc.)
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pruneOctree
private void pruneOctree()Reduces the octree until it has as many leaves (or less) than specified by thepaletteSize
argument in the constructor#OctreeColorQuantizer(int)
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setPaletteSize
public void setPaletteSize(int newPaletteSize)
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